Glioblastoma research 2006-2010: pattern of citation and systematic review of highly cited articles.

High and continuously increasing research activity related to different aspects of pathogenesis, epidemiology, diagnosis and treatment of glioblastoma has been performed between 2006 and 2010. Different measures of impact, visibility and quality of published research are available, each with its own pros and cons. For this review, article citation rate was chosen. Articles were identified through systematic search of the abstract database PubMed followed by analyses of total number of citations and proportion of highly cited articles, arbitrarily defined as those with ≥100, 50-99, and 25-49 citations, respectively (citation database Scopus). Overall 5831 scientific articles on the subject were published during this time period. 1.5% of all articles accumulated at least 100 citations, 3.2% were cited between 50 and 99 times, and 7.5% were cited between 25 and 49 times. Among the 10 most cited articles, 7 reported on genomic analyses, molecular subclasses of glioblastoma and/or stem cells. Overall, 18 randomized clinical trials were published between 2006 and 2010, including those with phase II design. Thirty-nine percent of them accumulated at least 50 citations and 72% were cited at least 25 times. In general, annual citation rate appeared to gradually increase during the first 2-3 years after publication before reaching high levels. A large variety of preclinical and clinical topics achieved at least 25 citations. However, areas such as quality of life, side effects, and end-of-life care were underrepresented. Efforts to increase their visibility might be warranted.